


Casus Belli

by GooseAndGold



Category: Bleach
Genre: Alternate Universe - Canon Divergence, College-Age Ichigo, Did you know that Grimmjow is an idiot, Did you know that Ichigo is an idiot, Gen, Humour, M/M, Post-Canon, Pre-Slash
Language: English
Status: Completed
Published: 2020-12-30
Updated: 2020-12-30
Packaged: 2021-03-11 00:20:27
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,325
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28436019
Author URL: https://archiveofourown.org/users/GooseAndGold/pseuds/GooseAndGold
Summary: Drawing closer, Ichigo rounds a corner and gets hit by reiryoku like the air off a blast furnace, and it almost makes him stagger. He has to push through the crowd, to reach toward the source of it. The only advantage he has right now is his masked reiatsu—the element of surprise. He completely ignores a woman trying to give him a flyer. Tries not to push too hard to squeeze past a grandpa walking a stiff-looking old dog. Makes it up to the crowded sidewalk at the intersection all that spiritual pressure is emanating from. He—"Grimmjow?"Ichigo has been left to lead his normal human life, as a normal college student. There's no way it'll last.
Relationships: Grimmjow Jaegerjaques & Kurosaki Ichigo, Grimmjow Jaegerjaques/Kurosaki Ichigo
Comments: 7
Kudos: 149





	Casus Belli

**Author's Note:**

> Casus Belli (noun): An occasion provoking or justifying a war.
> 
> ~~~
> 
> It's been so long since I watched/read Bleach that I honestly can't remember if Grimmjow knows that Ichigo is a human. If he does know that, theeen...then this is an AU, dear reader.
> 
> This is a pre-slash one-shot. If people like it a bunch, then I will find it in me to write more.
> 
> Enjoy!

* * *

Ichigo is halfway through stuffing a hamburger in his mouth when he senses it. _Big_ reiryoku, not like some aimless gillian. It's wild, intense. Pushes up against his senses like something roaring in his ear.  
_  
Arrancar_.  
  
He chokes momentarily around his McDonald's, but then he's up before he can think about it. He dumps his tray, pushes through the crowd out into the November chill, breaking into a jog. He's in Shibuya, so the sidewalks are absolutely packed with people, and he has to dart out onto the curb to actually pick up any kind of pace.  
  
_What the fuck is an Arrancar doing in Tokyo?_  
  
There were three Arrancar left in the world, last time anyone bothered to tell him anything. Nelliel. Harribel. Grimmjow.  
  
He doesn't let himself even start hoping that it's Nel, because the universe is an asshole and as soon as he wishes for something like that, it _absolutely_ won't come true.  
  
He's breathing hard as he continues toward the feeling. He doesn't have Kon with him here. He didn't even bring his damn single-use emergency badge with him—he was just going down the street from his place for a Big Mac. Like an _idiot_. He can only cross his fingers that he's not running across the dirty pavement straight into the jaws of death.  
  
Drawing closer, he rounds a corner and gets hit by reiryoku like the air off a blast furnace, and it almost makes him stagger. He has to push through the crowd, to reach toward the source of it. The only advantage he has right now is his masked reiatsu—the element of surprise. He completely ignores a woman trying to give him a flyer. Tries not to push too hard to squeeze past a grandpa walking a stiff-looking old dog. Makes it up to the crowded sidewalk at the intersection all that spiritual pressure is emanating from. He—  
  
" _Grimmjow_?"  
  
Blue eyes snap over to his like a crack of lightning.  
  
_Element of surprise. Nailed it._  
  
Grimmjow pushes off the telephone pole he'd been leaning against and stalks forward. The crowd can't see him, but it parts for him anyways, people shuffling nervously and shuddering like someone stepped on their graves.  
  
Grimmjow isn't that much taller than Ichigo. Just a few inches, really. But he might as well eclipse the damn sun for how he looms. Ichigo belatedly takes his eyes away from where Pantera is slung through his belts, still sheathed, to catch the look in the Arrancar's eyes.  
  
He looks...stunned?  
  
"Kurosaki?"  
  
"I'm...yep," Ichigo says, frozen. "That's me."  
  
"You're alive?"  
  
Ichigo frowns. He tucks his hands into the ample pockets of his parka. "You knew that already," he says, off balance. It comes out like a question. He did...know that, right? Yes, he definitely did. He had to have known that Ichigo survived Yhwach.  
  
"Or is this a gigai or something," Grimmjow continues, like he didn't speak at all.  
  
_What?_  
  
"Gigai?” He looks down at his own front. “W—no! I'm a human! I told you this befo—" Ichigo glances to the side and sees that he is earning very weird looks. His cheeks go redder than they already were from running in the cold. "Can we talk somewhere quieter?" Ichigo hopes his expression is sufficiently pleading.  
  
Grimmjow, whose expression had been open with surprise, narrows his eyes and jerks his chin toward the tight alleyway between a florist and a ramen shop. Ichigo follows his lead through the press of people, who start milling forward as the pedestrian light goes. His eyes take in Grimmjow's shoulders, his wild mess of hair, his unchanged outfit. Ichigo is still kind of reeling. It occurs to him as he steps into the shadowed alley that he probably could have still turned around and tried to run, or something. Made a half-assed effort at surviving. Too late now.  
  
"You're human," Grimmjow presses immediately, the moment he turns around. The last time his face was this close, Ichigo was fighting for his life.  
  
Ichigo takes a bracing breath. "Yeah. Yes. Wait, I've told you that before. I know you knew that."  
  
"Didn't believe you."  
  
_What._ "Wh—you...you didn't _believe_ me?"  
  
Grimmjow just shrugs, and then leans in—leans in _close_. Ichigo freezes, with sudden images of panther fangs in his jugular, and him bleeding out in his stupid squishy human body in an alley in Tokyo.  
  
At his ear, Ichigo hears a sharp inhale of breath. Grimmjow pulls back, and his eyes are assessing as he scans up and down Ichigo's jeans-and-parka attire. "You're actually a human." His eyes narrow, mirroring the slant of his estigma. "How'd you manage that?"

His meagre self-preservation instincts are really being tested right now. “I've been a human my whole life.” He says it patiently. Politely, so as to not piss the hollow off by stating the obvious.

“Fuck off,” Grimmjow growls. But mercifully, he leans back, arms crossed, and doesn't point anything sharp in Ichigo's direction. “Why're you a shinigami then?”

“I'm a _substitute_ shinigami,” he explains. “I'm a—” A what? “...it was...a temp gig,” he finishes, lamely. His eyes slip away from Grimmjow's face and down to the pavement.

“A substitute,” Grimmjow replies. “A temp.”

“Yeah.” He nods. “Actually, it started because Rukia got injured, so I need to—”

“Who the fuck is Rukia?”

“Oh my _god_ ,” Ichigo growls. He holds his hand to about hip height. “This tall, black hair, Captain of the Thirteenth Division?”

He gets a blank stare in return. “And you were covering for this shinigami captain.” Grimmjow's tone of voice is dripping with skepticism.

“Well, not after a while. She wasn't a Captain then, anyways. I just...happened to be around when shit went down.” And now no shit is going down, so no one needs him around. Simple as that.

Grimmjow shrugs and turns, heading out of the alleyway and back toward the busy streets.

“Uh, where are you going?” Ichigo asks, momentarily forgetting he absolutely _had not_ wanted this conversation.

“To kill the shinigami captain,” Grimmjow says over his shoulder.

“Woah! _Fuck_ no.” Ichigo reaches out, grabs Grimmjow by the shoulder. He's immediately pulled along, like he doesn't weight anything at all. “Hold up. Hold up. Don't go kill Rukia.”

Grimmjow stops, and glances over his shoulder—first at Ichigo's hand, which has a death grip on his jumpsuit, then at Ichigo himself. “Why the fuck not?” There's a challenge in his eyes. In his voice.

Ichigo's mouth opens. Closes. 'What did she ever do to you' will not be a good enough reason, not for an arrancar.

“She tougher than you, this full-time shinigami?”

“Well, no, but—”

“Then why's she the Captain and you're just a temp?”

Ichigo yanks on the shoulder under his hand, and Grimmjow deigns to turn with it. “Because I'm a goddamn human!” He yells. _What is so difficult about this!_

Grimmjow grabs his wrist, then. Ichigo sees it coming, but he's not fast enough to stop it. Grimmjow slides the sleeve of his parka halfway down his forearm, and turns it this way and that. Squeezes until Ichigo winces. Pulls his arm up above his head and watches Ichigo strain at their difference in heights.

“What are you doing,” Ichigo asks irritably. It actually might be worth getting murdered in this alleyway just so he wouldn't have to keep being treated like a marionette. He's gonna be nicer to Kon from now on.

“You're weak as shit.” Grimmjow's face is scrunched up in a constipated frown. He lets go of Ichigo's wrist. Ichigo is opening his mouth to reply something like 'No shit, dumbass,' when he feels hands under his armpits. His feet leave the ground.

Ichigo's hands fly to Grimmjow's arms, where they're holding his body aloft like he's a goddamn infant.

“Put me. The fuck. _Down_ ,” he growls.

Grimmjow's eyes narrow, but he sets him down.

And then he doesn't let go.

“Excuse y—”

“Are you stuck as a human forever now?” Grimmjow barrels over him.

Ichigo sighs. How does he answer that? “I have a badge. I can turn into a shinigami.”

“Use it.”

“It's at my apartment.”

“Go to your apartment and use it.”

“I can only use it once,” he admits. “It's...for emergencies.”

Then the hands are gone from his sides, and in the next moment, the flat of Grimmjow's palm slams into his chest, and his back is forced against the cold brick wall of the ramen shop. The arrancar leans in. His eyes glare hot into Ichigo's, once he's done blinking the stars out of his vision. “You're this weak and you don't carry around your fuckin' emergency shinigami button with you? You lookin' to die?”

Ichigo tries to push off the wall, to absolutely zero effect. The hand against his sternum is like steel. “I was eating a goddamn Big Mac! I wasn't expecting to have to suit up for battle! You wanna kill me? Then fine! I guess I can't stop you, can I? But it's not going to be much of a fucking fight.”

The hand slides off his chest with a swish against the polyester. “Ain't gonna kill you, Kurosaki,” Grimmjow tells him.

Well thank _fuck_ for that. He doesn't actually want to die. But he doesn't let his relief show, just on principle. “So what, then?”

Grimmjow tucks his hands into his pockets. Tips his head. “Gonna bring you home.”

Ichigo splutters. “Take me—what, to Hueco Mundo?”

Grimmjow scoffs. “No, dumbass. Said your badge was at your apartment. So where d'you live?”

“I also said I could only use the badge once. For emergencies.”

“So you're chasin' around arrancar reiryoku in a body made outta tissue paper without your fuckin' emergency badge.” Grimmjow looks him up and down. He spits on the ground. “Takin' you home and makin' you use it.”

“So I went to get lunch as a human being, like every other human on earth does, and you're gonna carry me bridal-style through my front door and make me fight you?”

“Ain't like every other human. Use the badge, and then stay that way.”

Ichigo crosses his arms. “And if I refuse? Or just go back in my body? Then what'll you do, kill me?” _Hah. Checkmate._

Grimmjow seethes, but at that moment, Ichigo's phone buzzes. He has three alert sounds on his phone—one for Soul Society-related people, one for Yuzu, and one for everybody else. This is the Soul Society one, so he doesn't ignore it. He fishes into his jacket pocket and taps on the screen.

Renji – 1:46pm

_there's crazy reiryoku near you, man_

_you good?_

_Is_ he good? He glances up from his phone to where Grimmjow is still glaring at him. His whole face is in deep shadows that the grey November sun can't reach in this alley, but his estigma seems almost like a neon light under his eyes.

You – 1:47pm

_yeah, all good_

Ichigo tucks the phone away, and keeps his frost-numb fingers in his pockets. “What're you doing in Tokyo, Grimmjow?”

“The tourist thing.” Ichigo levels him a flat look. “It's none of your fucking business what I'm doin', shini—Kurosaki. I'm takin' you to your apartment, and I'm makin' you use the damn badge. That's what I'm doin' now.”

Grimmjow grabs his wrist—again, ow—and begins to pull him out of the alley by the arm.

Ichigo pushes at the hand on pure instinct, and growls “Are you going to drag me the whole way there? Nobody can see you, jackass. I look like a mime pretending to walk a dog. You don't know where I live, anyways.”

His wrist is released. Ichigo huffs, and resists the urge to rub at it. Asshole.

“Then walk, if you're walking.” There's no room for argument.

“Grimmjow,” Ichigo argues anyways. He hopes the tone in his voice is rock-steady, because really there's nothing he can do right now if Grimmjow is set on dragging him across the city, pinning him to his apartment floor, and pulling his soul out of his own mouth by force. “I'm not using the badge to fight you. If I had unlimited uses, then sure, whatever, we could make an appointment to beat the shit outta each other sometime.” He's not even lying. He'd honestly like that. “But if I use it, that's it. That's all I get. If something bad comes around, then what? It's just me and my 'tissue paper body.' I don't wanna be useless when it counts.”

Grimmjow looks him up and down again. He tilts his head thoughtfully. “If something that bad came around that Soul Society had to pull you off the bench, they'd give you another badge. Like whatever you had before.”

Ichigo shrugs. “Probably. Maybe. I'm not gonna risk it. You're so worried about me stubbing my toe while buying lunch, maybe you shouldn't _make_ me risk it.”

Grimmjow's hands go back into his pockets. He rolls his shoulders, suddenly casual and irreverent. “Fine. Don't use it for now.”

“You—huh?” Ichigo blinks. Talk about conversation whiplash.

“Don't use the badge for now, but keep it on you, or I duct-tape it to your face.”

That was way too easy. Ichigo doesn't trust it _at all_. “But...?”

“But nothing,” Grimmjow tells him. He turns away, but speaks back over his shoulder, an eye locked on Ichigo's face. “If Soul Society's got a big enough threat barin' down on it, they'll give you your badge back. Simple as that.”

And then he fucking disappears.

Ichigo blinks into the murky shadows of the alley. He feels like he just got slapped in the face.

_'A big enough threat...'_

“Shit,” he mutters. He pulls his phone out of his pocket. Opens his texts, and pulls up Renji's message where it's still at the top of his contacts.

You – 2:02pm

_i think i just fucked up._

* * *

**Author's Note:**

> Come talk to me on Twitter!
> 
> http://twitter.com/leedveed


End file.
